[Pw_forum] Doubt on pseudopotential
axel.kohlmeyer at theochem.ruhr-uni-bochum.de
Sun May 8 12:19:04 CEST 2005
On Wed, 4 May 2005, Eduardo Ariel Menendez P wrote:
EM> Several elements of the 6th row have 4f elBectrons. Hence, I think that
EM> valence wavefunctions calculated with plane waves should be orthogonal to
EM> the core 4f orbitals, and an l=3 channel must be included in the
EM> pseudopotential (otherwise it is the local part). See, for instance, the
EM> Pb pseudopotential
EM> with the core 4F orbitals. I also checks Tl, Au,Ta, and it is the same.
EM> For this lack of an F channel there is surely a good reason.
EM> Can someone explain me that reason, please?
i have not created those potentials, so i don't know for sure, but
most likely the f-channel was left out, because it had little effect.
the 4f-orbitals are very close to the core, so for elements with
the 4f orbitals filled, there is little effect from them apart from
a 'contraction' of the other orbitals. thus chemically, many elements
from the 6th row are very similar to their counterparts in the 5th row.
there are a exceptions, though...
a similar situation exists e.g., for the 3d states. please see the
section 'Choosing the valence-core partition' in the pseudo-gen.tex
document in the atomic_doc directory of the espresso packages.
EM> Best regards
EM> Eduardo A. Menendez Proupin
EM> Department of Physics
EM> Faculty of Science
EM> University of Chile
EM> Las Palmeras 3425
EM> Ñuñoa, Santiago
EM> Phone: 56+2+678 74 11
EM> Pw_forum mailing list
EM> Pw_forum at pwscf.org
Dr. Axel Kohlmeyer e-mail: axel.kohlmeyer at theochem.ruhr-uni-bochum.de
Lehrstuhl fuer Theoretische Chemie Phone: ++49 (0)234/32-26673
Ruhr-Universitaet Bochum - NC 03/53 Fax: ++49 (0)234/32-14045
D-44780 Bochum http://www.theochem.ruhr-uni-bochum.de/~axel.kohlmeyer/
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